In typical feeder circuits, several types of lines such as microstrip lines and strip lines are used to connect between circuits.
In planar antennas, for example, lines for connecting between a feeding point (an output end) and an array of radiating elements are provided between the feeding point and the radiating elements.
However, in the case where the radiating elements are densely arranged, the lines placed near the radiating elements are close to one another, inducing electrical coupling between the lines which causes deterioration in the radiation pattern and reflection characteristic of the planar antenna.
Patent Literature 1 discloses a technique that includes a dielectric substrate stacked over an aperture plane of a planar antenna, and a polarization grid configured to generate desired polarized waves.